Field of the Invention
The present invention relates to a power storage service system.
Priority is claimed on Japanese Patent Application No. 2015-244220, filed Dec. 15, 2015, the contents of which are incorporated herein by reference.
Description of Related Art
An assembled battery system classified for a large stationary generally has a storage capacity of several hundreds of kWh or an input and output power capacity of more than several tens of kW. In recent years, it began to be assumed that a system with a storage capacity of 100 MWh class. A large capacity is to generally realize by combining hundreds to thousands pieces of unit cells of a several tens to several hundred Ah.
In such as the assembled battery system, it has been made to monitor state of unit cells by using operation state information of an equalization circuit. The assembled battery system is described in Patent Document 1 (Japanese Patent No. 4529246), and Patent Document 2 (Japanese Patent No. 3975796).
An abnormality detector of the assembled battery described in Patent Document 1 determines the abnormality of the assembled battery based on the operation frequency of the capacitance equalizer to achieve the equalization of the remaining capacities of the plurality of unit cells (SOC). There is judged to be abnormal when the operation frequency larger than or equal to at least a predetermined frequency. Further, an abnormality detector of the assembled battery described in Patent Document 2 determines an abnormality of the assembled battery based on the discharge quantity of the capacity equalization means to achieve the equalization of the remaining capacities of the plurality of unit cells (SOC), the unit cell which the discharge quantity is less than predetermined threshold value is determined that it is the unit cell which is not able to charge a sufficient electric quantity because of its deterioration is determined to be abnormal.
The abnormality detector of the assembled battery described in Patent Document 1 merely determines an abnormality, and it is impossible to know the time margin until the abnormality is occurred. The abnormality detector of the assembled battery described in Patent Document 2 can avoid the problem that the unit cells are determined abnormal in accordance with an equalization circuit operates even though the unit cells are normal in a case that the small discharge is repeatedly executed. But it is merely determination of the abnormality, it is also impossible to know the time margin until the abnormality is occurred. The installed assembled battery system is in the trend of the market which the storage capacity is required for increasing in the future, it is apparent that the number of the unit cells are increased. In the prior art, it needs to stop the system in each occurring the abnormality, and it needs to confirm the state of the system and perform the maintenance task. It is clear that the operating time of the assembled battery system will decrease, unless the abnormal incidence of the unit cells is significantly improved.
Further, when the abnormality is occurred in the installed assembled battery system, it is extremely important to safely stop the actual operation for the system itself and the service which is given power from the system, to launch alternatives, and to secure time for arranging repair parts and secure maintenance operators, even though the unit cell is irreversible deteriorated (e.g., over discharge). However, the prior art does not disclose a mechanism that can be measured and securing of the time.
If it cannot solve the above mentioned problems, it is impossible for the power company who adopts a KPI (Key Performance Indicator) derived from a SAIDI (annual average power failure time per subscriber) and a SAIDI (annual average number of power failures per subscriber) to pull out the original utility from the assembled battery system that is introduced for the KPI improvement.
On the other hand, it is well known that the quality improvement efforts is carried out every day such as reducing an uneven of the product, adding of the inspection processes, and the pre-shipment screening for the purpose of reducing the probability of the occurring abnormality due to the characteristics of the unit cells. However, all these matters also lead to an increasing of the manufacturing cost and profitability of one or more of unit cell manufacturers, assembled battery system manufacturers, and the user of assembled battery system are deteriorated. In addition, it is impossible to completely eliminate probability of the abnormal expression risk in the quality control of the manufacturing process, to lead the risk to zero. It is obvious that the abnormality is expressed with a certain probability. Thus, there are necessaries to manage the abnormal expression risk in the assembled battery system side which includes the unit cells.
The present invention is a power storage service system including: quantitatively grasping the time leading up to the expression of the abnormality; capable determining possible or impossible of avoiding stopping of the function of the assembled battery system. According to the invention, a maintenance operator and a maintenance service supplier of the assembled battery system have a time margin to plan a response schedule and to prepare responding, and it can reduce the cost of responding to the maintenance by reducing and optimizing the number of response.